Latex chloroprene rubber

Emulsion polymerization is the most important process for production of elastic polymers based on butadiene. Copolymers of butadiene with styrene and acrylonitrile have attained particular significance. Polymerized 2-chlorobutadiene is known as chloroprene rubber. Emulsion polymerization provides the advantage of running a low viscosity during the entire time of polymerization. Hence the temperature can easily be controlled. The polymerizate is formed as a latex similar to natural rubber latex. In this way the production of mixed lattices is relieved. The temperature of polymerization is usually 50°C. Low-temperature polymerization is carried out by the help of redox systems at a temperature of 5°C. This kind of polymerization leads to a higher amount of desired trans-1,4 structures instead of cis-1,4 structures. Chloroprene rubber from poly-2-chlorbutadiene is equally formed by emulsion polymerization. Chloroprene polymerizes considerably more rapidly than butadiene and isoprene. Especially in low-temperature polymerization emulsifiers must show good solubility and... 

In 1994, the worldwide consumption of rubber was approximately 14.5 million tons a year, of which about 40% consisted of natural rubber. Natural rubber is produced as latex by tropical rubber trees (Hevea brasiliensis). It is processed locally and therefore the quality of natural rubber fluctuates remarkably [ 140]. Due to increasing demand for rubbers, combined with a decreasing production capacity in Asia and a vast increase in labor costs, the price of natural rubber is still rising sharply. In 1990-1994, the average price of natural rubber was about 0.38 /lb, while in 1996 it was already over 0.80 /lb. The remaining 60% of the articles were manufactured from synthetic petroleum-based rubbers such as isoprene rubber, styrene-butadiene rubber, chloroprene rubber and polyurethanes. The quality of synthetic rubbers is constant, and their price varies between 2 and 5 US per kilogram [137-140]. 

Butadiene is used primarily in the production of synthetic rubbers, including styrene-butadiene rubber (SBR), polybutadiene nibber (BR), styrene-butadiene latex (SBL), chloroprene rubber (CR) and nitrile rubber (NR). Important plastics containing butadiene as a monomeric component are shock-resistant polystyrene, a two-phase system consisting of polystyrene and polybutadiene ABS polymers consisting of acrylonitrile, butadiene and styrene and a copolymer of methyl methacrylate, butadiene and styrene (MBS), which is used as a modifier for poly(vinyl chloride). It is also used as an intermediate in the production of chloroprene, adiponitrile and other basic petrochemicals. The worldwide use pattern for butadiene in 1981 was as follows (%) SBR + SBL, 56 BR, 22 CR, 6 NR, 4 ABS, 4 hexamethylenediamine, 4 other, 4. The use pattern for butadiene in the United States in 1995 was (%) SBR, 31 BR, 24 SBL, 13 CR, 4 ABS, 5 NR, 2 adiponitrile, 12 and other, 9 (Anon., 1996b). 

Accel TP AI3-08293 Butyl namate Carbamic acid, dibutyidithio-, sodium salt Carbamodithioic acid, dibutyl-, sodium salt Dibutyidithiokarbaman sodny EINECS 205-238-0 HSDB 2900 Octopol NB-47 Pennac Pennac SDB Sodium DBDT Sodium dibutylcarbamodithioate Sodium dibutyidittiiocarbamate Sodium N,N-dibutyldithiocarbamate Tepidone Tepidone rubber xcelerator USAF B-35 Vulcacure Vulcacure NB. Ultra accelerator for SBR and natural rubber latex compounds in polymerization of chloroprene rubber, especially for latex compounds where copper staining of zinc salt dithiocarbamates is a problem. 

Baypren Latex Anionic lattices of chloroprene rubber, CR Polysar/Bayer AG... 

Synonyms N,N -dibutyl-thiourea N,N-dibutylthiourea N,N -di-n-butylthiourea i,3-dibutyl-2-thiourea 1,3-dibutylthiourea Uses accelerator for mercaptan-modified chloroprene rubber activator for ethylene-propylene-diene terpolymers and natural rubber antidegradant for natural rubber latex and thermoplastic styrene-butadiene rubber A... 

Although many different polymers were investigated for use in PPCC, latexes are the most widely used binders. The latexes that are in general use are styrene-butadiene rubber (SBR) and chloroprene rubber (CR) which are elastomeric polyacrylic ester (PAE), ethlene-vinyl acetate (EVA) and poly(styrene-acrylic ester) (SAE) which are thermoplastic. Besides latexes, epoxy resins, which are thermosetting, are also used in PPCC [11, 17]. 

Styrene/butadiene rubber (emulsion plus solution) Styrene / butadiene emulsion rubber-latex Butadiene rubber Isoprene rubber Chloroprene (or neoprene) rubber... 

Shanxi Synthetic Rubber Group (SSRG) is a first-class, large-scale, state-owned enterprise producing chloroprene rubber, PVC resin, chlorinated PE, caustic soda, calcium carbide, chlorine liquid and cement. The main product of SSRG, chloroprene rubber, has an annual capacity of 25 000 tonnes per year including five types each of dry rubber and rubber latex. 

Rubbers. Plasticizers have been used in mbber processing and formulations for many years (8), although phthaHc and adipic esters have found Htde use since cheaper alternatives, eg, heavy petroleum oils, coal tars, and other predominandy hydrocarbon products, are available for many types of mbber. Esters, eg, DOA, DOP, and DOS, can be used with latex mbber to produce large reductions in T. It has been noted (9) that the more polar elastomers such as nitrile mbber and chloroprene are insufficiendy compatible with hydrocarbons and requite a more specialized type of plasticizer, eg, a phthalate or adipate ester. Approximately 50% of nitrile mbber used in Western Europe is plasticized at 10—15 phr (a total of 5000—6000 t/yr), and 25% of chloroprene at ca 10 phr (ca 2000 t/yr) is plasticized. Usage in other elastomers is very low although may increase due to toxicological concerns over polynuclear aromatic compounds (9). 

During 1973, at a chloroprene polymerization plant in the United States, airborne concentrations of chloroprene were found to range from 14 to 1420 ppm [50-5140 mg/m ] in the make-up area, from 130 to 6760 ppm [470-24 470 mg/m in the reactor area, from 6 to 440 ppm [22-1660 mg/m ] in the monomer recovery area and from 113 to 252 ppm [409-912 mg/ni l in the latex area (Infante et al., 1977). Concentrations in the air inside a Russian polychloroprene rubber plant were 14.5-53.4 mg/m (Mnatsakayan et al., 1972). In a Russian chloroprene latex manufacturing facility, chloroprene concentrations varied from 1 to 8 mg/m (Volkova et al., 1976). 

The major emulsion processes include the copolymerization of styrene and butadiene to form SBR rubber, polymerization of chloroprene (Fig. t -4) to produce neoprene rubbers, and the synthesis of latex paints and adhesives based mainly on vinyl acetate and acrylic copolymers. The product is either used directly in emulsion form as a paint or else the surfactants used in the polymerization are left in the final, coagulated rubber product. 

Emulsion polymerization is the basis of many industrial processes, and the production volume of latex technologies is continually expanding—a consequence of the many environmental, economic, health, and safety benefits the process has over solvent-based processes. A wide range of products are synthesized by emulsion polymerization, including commodity polymers, such as polystyrene, poly(acrylates), poly (methyl methacrylate), neoprene or poly(chloroprene), poly(tetrafluoroethylene), and styrene-butadiene rubber (SBR). The applications include manufacture of coatings, paints, adhesives, synthetic leather, paper coatings, wet suits, natural rubber substitutes, supports for latex-based antibody diagnostic kits, etc. ... 

When chloroprene was grafted onto cationic aminated starch, a latex was obtained that imparted wet strength to paper and also served as a pressureless adhesive for wood 2951 Starch dialdehyde when grafted with acrylonitrile, methyl methacrylate, or both, produced a biodegradable filler for poly (vinyl chloride) plastics.2942 Starch xanthates grafted with vinyl monomers were also used to produce additives for reinforced foamed rubber.2944,2945... 

Particularly thin articles (e.g., rubber gloves) are produced by dipcoating. In this case, the mold negative is dipped into a latex (a dispersion) or a paste for as long and/or as often as is necessary to obtain the desired thickness. The latex viscosity should be less than 12 Pa s the flow limit as low as possible. Latices of natural rubber poly(chloroprene), and silicones, as well as PVC pastes, are processed in this way. 

There are many types of waterborne laminating adhesives with widely differing applications and performance properties. Common waterborne textile adhesives include natural rubber latex, co-polymers of acrylic esters and acids, vinyl and vinylidene chloride, vinyl acetate, and chloroprene. Other, less common adhesives include starches, dextrin, and other polymers of natural origin. Characteristics of common waterborne adhesive used by the textile industry are given in Table 13.11. 

Rubb rS. Heavy petroleum oils, coal tars, and other predominantly hydrocarbon products have been used in rubber processing and formulations for many years. Esters such as DOA, DOP, and DOS, can be used with latex rubber, nitrile rubber, and chloroprene to reduce the Tg. The level of plasticizer is usually aroimd 10-15 phr. 

Another kind of monomer (repeating units) of interest is what is called diene. Ethylene and vinyl compounds are so-called monoene, compounds that have in them only one double bond, as you saw. Diene molecules have two double bonds in them. Butadiene CH2=CH-CH=CH2, isoprene CH2=C(CH3)-CH=CH2 and chloroprene CH2=CC1-CH=CH2 are important examples of diene. We have seen isoprene before it is the repeating unit of natural rubber latex. 

The monitoring of airborne monomer concentrations around subsequent processing operations may provide one index of the efficiency of such stripping. For example, Nutt has found chloroprene concentrations as high as 20 ppm around polychloroprene latex dipping, whilst 18-45 ppm of methyl acrylate has been found next to dies during the extrusion of Vamac ethylene/acrylic rubber at temperatures between 71 and 93°C. ... 

Synthetic rubber), for example, acrylate, acrylate-butadiene, butyl, ethylene-propylene, chloroprene, ethylene-propylene diene, latex, neoprene, nitrile-butadiene, polyisobutylene, polysulfide, silicone, styrene-butadiene, styrene-isoprene rubber thermoset vulcanizable elastomers thiol rubber urethane... 

Rubber Latexes For example, chloroprene latex. Alternative to solvent-containing contact adhesives... 

Latex is a stable dispersion of a polymeric material (Table 8.13) in an essentially aqueous medium. An emulsion is a stable dispersion of two or more immiscible liquids held in suspension by small percentages of substances called emulsifiers. In the adhesives industry, the terms latex and emulsion are sometimes used interchangeably. There are three types of latex natural, synthetic, and artificial. Namral latex refers to the material obtained primarily from the rubber tree. Synthetic latexes are aqueous dispersions of polymers obtained by emulsion polymerization. These include polymers of chloroprene, butadiene-styrene, butadiene-acrylonitrile, vinyl acetate, acrylate, methacrylate, vinyl chloride, styrene, and vinylidene chloride. Artificial latexes are made by dispersing solid polymers. These include dispersions of reclaimed rubber, butyl rubber, rosin, rosin derivatives, asphalt, coal tar, and a large number of synthetic resins derived from coal tar and petroleum. ... 

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